Source Citation

Abstract

Objective

To compare the effectiveness of a Mediterranean α-linolenic acid-rich diet with a
usual postinfarction diet in reducing mortality and morbidity in patients who have
had a first myocardial infarction (MI).

Design

5-year randomized, single-blind, controlled trial.

Setting

6 cardiology clinics in France.

Patients

605 patients (mean age, 53.5 y; 91% men) were < 70 years of age and had survived
an MI within 6 months before enrollment. Exclusion criteria were stage III or IV New
York Heart Association functional class heart failure; uncontrolled hypertension (systolic
> 180 mm Hg, diastolic > 110 mm Hg); incomplete exercise test due to angina,
ventricular arrhythmias, or atrioventricular block; and clinical instability after
angioplasty or coronary artery bypass. Of the patients randomized, 21 withdrew and
were included only in the total mortality analysis. Mean follow-up of the remaining
584 patients was 92%.

Intervention

Patients allocated to the Mediterranean diet (n = 302) received a 1-hour educational session outlining the diet (more bread, root
and green vegetables, fish, poultry, and fruit; less meat; and butter and cream replaced
with a rapeseed [canola] oil-based margarine provided by the study, or olive oil).
At 8 weeks and then annually, a diet survey and further counseling were completed.
Control patients (n = 303) received standard dietary advice from hospital dieticians or attending physicians.

Main Outcome Measures

Death from cardiovascular causes and nonfatal acute MI.

Main Results

During the 1 to 5 years of follow-up, patients on the Mediterranean diet consumed
more bread, fruit, and margarine, and less butter, cream, and meats than patients
in the usual diet group (P < 0.01). Patients in the Mediterranean diet group had fewer deaths from cardiovascular
causes (3 [1%] vs, 16 [5.3%]; {95% CI for the 4.3% difference, 1.5% to 7.0%}*) and
fewer nonfatal MIs (5 [1.7%] vs. 17 [5.6%]; {CI for the 3.9% difference, 1.0% to 7.0%}*)
than those in the usual diet group.

Conclusion

In patients who have had a recent myocardial infarction, a Mediterranean α-linolenic
acid-rich diet reduced the incidence of both death from cardiovascular causes and
nonfatal acute myocardial infarction compared with a usual postinfarction diet.

Commentary

The study by de Lorgeril and colleagues is an important addition to both the scientific
and clinical literature concerned with the relation between diet and coronary heart
disease.

After an initial MI, 303 patients were placed in a control group with standard dietary
counseling, and 302 were placed in an experimental group with a more rigid diet containing
less saturated fat, cholesterol, and linolenic acid, but with more oleic and α-linolenic
acids. The experimental group on a Mediterranean-type diet consumed more bread, vegetables,
fish, and olive or canola oil than did the control group, and had less meat, butter,
and cream. The experimental group also pursued the approach of "no day without fruit."

The results are impressive in terms of reduced mortality and cardiac events, not only
with statistical but with clinical significance. 20 deaths occurred in the control
group compared with 8 in the experimental group. In terms of overall primary end points,
33 events occurred in the control group and 8 in the experimental group.

The statistical design and presentation of this study is excellent, and the review
of the literature makes the article valuable to researchers as well as clinicians.
The authors recognize that they have not established the exact reason for success
of the dietary intervention but lean toward an explanation related to the high intake
of α-linolenic acid in the experimental group. They cite epidemiologic evidence from
the Japanese, who have a high intake of α-linolenic acid in the form of canola and
soybean oils. The same result is achieved in other populations by the intake of walnuts
and other foods. The authors cite other differences and potential explanations, including
vitamin C, vitamin E, and other antioxidants, the levels of which were higher in the
experimental group.

As a basis for future research, this is an important article. As a basis for prudent
dietary changes relevant to clinicians and their patients, this work is a guideline
of a practical sort related to a Mediterranean-type diet—with no passport or airline
ticket required.